The present disclosure is directed to mine doors and more particularly, an access door for personnel through ventilation mine doors.
Prior to the introduction of automated mine doors, mine operators used “snappers” to open and close doors on the haulage road, so that the motorman would not have to stop. The snapper would open the door, wait for the last car to pass, close the door and then run to get back on the train/tram for the remainder of the trip. In practice, however, often times the motorman would not stop, he would only slow down so that snapper could run ahead of the locomotive and open door. This practice proved unsafe for the miners, the motorman, and detrimental to both the locomotive and the doors.
The advent of machine-assisted mine doors helped alleviate some of the dangers; however such doors still required manual engagement of the machines to open and close the doors. Furthermore, the pressures being exerted on these doors also increased, as ventilation became more effective and powerful due to increases in operating temperatures, depths, mine size, etc. As mines reach greater depths, the size of the doors must increase to accommodate larger and larger equipment, i.e., the easily accessible minerals have already been retrieved, leaving the harder to access deposits farther underground. The increase in size has led accordingly to increases in the power, both applied and consumed, in opening and closing these doors.
The typical mine door includes two wings, which either swing inward or outward, depending upon the configuration. The strength, size, and functional machinery for proper function substantially increase in high-pressure environments. Thus, when either opening or closing, the pressure provides assistance. However, this standard design is hindered in the reverse operation, wherein not only the mass of the doors must be moved, but also the opposing flow of air must be overcome to properly close the mine doors. As will be appreciated, such standard design is notably hindered in speed of operation as a result of the wings of the door both swinging either inward or outward, as well as negatively impacted by the air pressure, which only helps either open or close and hindering the opposite.
Modern mine doors may be tasked with operating under constant pressures including 400,000 inch/Lb./torque, 800,000 inch/Lb./torque, and 1,200,000 inch/Lb./torque. As stated above, in most existing mines, the more readily accessible minerals have generally been mined out, requiring the exploitation of veins located deeper underground. In parallel with this depth increase is an increase in the types of vehicles and equipment employed in the mines, as well as an increase in the speed of mining operations that advances in the mining arts have wrought. This increased speed of operations requires that mine doors be capable of operating a large number of cycles each day, e.g., 300 cycles per day, 365 days a year. Due to these demanding conditions, the moving components of a mine door are under increased strain and wear.
Attempts to alleviate some of these issues in high-pressure environments include each wing of the door swinging in an opposite direction. This allows for the high-pressure to facilitate opening and closing of the door, thereby assisting the machinery in the process. A further benefit of such a design includes the coupling of both the top and bottoms of each wing together via respective connecting bars, thus synchronizing the opening/closing of the wings. The power for such wing generally includes at least two pistons or other means of opening or closing the wings. Such embodiments still require an unreasonable amount of time to fully open or close, and may include connecting bars that are frequently damaged by equipment transiting the doorway, e.g., either running over the lower connecting bar or impacting the upper or top connecting bar. These types of mine door embodiments require frequent maintenance and repair due to the damage from machinery and the number of operating components.
These large doors may exceed twenty feet in height and twenty-five feet in width, requiring large amounts of effort to open or close simply by virtue of the mass of the door involved. Having to open and close these doors for each miner accessing the shaft places increased wear on the components of the doors, consumes power, and allows substantial air through, negating the benefits inherent in ventilation doors. The pressure exerted on the door may further impact operations, particularly when power is lost during emergencies. Without power, these large doors become severe obstacles to miners trying to evacuate the mine. Furthermore, in the event of partial cave-ins, one or both wings may be blocked, preventing either or both wings from swinging open, thereby trapping the miners or other personnel.
Personnel access doors within ventilation doors currently are hinged affairs, requiring a ninety-degree pivot in order to open. Miners are forced to contend with not only air pressure in opening and closing the door, but also the same concerns as presented above with respect to cave-ins preventing the pivoting. For example, when transiting such a door, the miner may have to use an inordinate amount of effort to open the door into the wind, but upon release the door slams shut, potentially causing damage to the door or injury to the miner.
Accordingly, what is needed is a personnel access door within an automated, high-pressure mine door to provide economical, safe, efficient, and easy access to personnel through ventilation mine doors, means of escape in times of emergency, and the like. Preferably, such access door should be capable of incorporation into ventilation control doors for all types of track and trackless mines, including, e.g., coal, uranium, salt, gypsum, clay, gold, potash, titanium, copper, molybdenum, platinum, etc.